Optical laminate with surface protection film

Abstract

Provided is an optical laminate with a surface protection film that can suppress the generation of air bubbles and adhesive residue while improving antifouling properties. [Solution] The optical laminate 10 comprises a transparent film substrate 11, an antifouling layer 12, and a surface protective film 13 in this order. The surface protective film 13 has a substrate layer 14 and an adhesive layer 15. The antifouling layer 12 and the adhesive layer 15 are in contact with each other. The surface hardness of the main surface 15a of the adhesive layer 15 on the antifouling layer 12 side is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. The water contact angle of the main surface 12a of the antifouling layer 12 on the adhesive layer 15 side is 115° or more. The adhesion strength between the antifouling layer 12 and the adhesive layer 15 is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

Description

[Technical field]

[0001] The present invention relates to an optical laminate with a surface protective film. [Background technology]

[0002] Antireflection films arranged on the outermost surface of image display devices, position detection films for touch panels, window films attached to window panes or show windows, and the like are used in a state where they can be touched from the outside, and are therefore susceptible to contamination by fingerprints, hand marks, dust, etc. For this reason, an antifouling layer is provided for the purpose of preventing contamination from the external environment and facilitating the removal of adhering contaminants.

[0003] In order to prevent these optical films (optical laminates) from being scratched or contaminated before use during processing, transportation, etc., a surface protective film is temporarily attached to the surface of the optical laminate (more specifically, the surface of the antifouling layer) (see, for example, Patent Document 1). Hereinafter, an optical laminate to which a surface protective film is temporarily attached may be referred to as an "optical laminate with a surface protective film" or simply as an "optical laminate".

[0004] In the optical laminate with a surface protective film (laminated plastic film for optical filters) described in Patent Document 1, an adhesive layer made of a pressure-sensitive adhesive and a release film (release liner) are laminated in that order on the side opposite the surface protective film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-151996 A Summary of the Invention [Problem to be solved by the invention]

[0006] When an image display device is manufactured using the optical laminate described in Patent Document 1, for example, after peeling off the release liner of the optical laminate, the exposed adhesive layer is attached to an image display panel, and in this state, a process (high-temperature, high-pressure process) is carried out in which the image display panel and the adhesive layer are allowed to blend under high temperature and high pressure. The high-temperature, high-pressure process is usually carried out in a state in which a surface protective film is temporarily attached.

[0007] On the other hand, the antifouling layer tends to have low adhesion to the surface protective film due to its tendency to easily repel moisture and oil. For this reason, air bubbles may be generated between the antifouling layer and the surface protective film (more specifically, the adhesive layer of the surface protective film) during the high temperature and high pressure process. If air bubbles are generated between the antifouling layer and the surface protective film, it may be judged as a defective appearance. Hereinafter, the defect of air bubbles being generated between the antifouling layer and the surface protective film (more specifically, the adhesive layer of the surface protective film) under high temperature and high pressure may be simply referred to as "air bubble generation".

[0008] Furthermore, if the adhesive strength of the pressure-sensitive adhesive layer of the surface protective film is increased in order to improve the adhesion between the anti-fouling layer and the surface protective film, glue residue may be generated on the surface of the anti-fouling layer when the surface protective film is peeled off from the anti-fouling layer.

[0009] It is difficult to suppress the occurrence of air bubbles and adhesive residue while improving the antifouling properties of the antifouling layer using only the technique described in Patent Document 1.

[0010] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an optical laminate with a surface protective film that can suppress the generation of air bubbles and adhesive residue while improving antifouling properties. [Means for solving the problem]

[0011] <Aspects of the present invention> The present invention includes the following aspects.

[0012] [1] An optical laminate with a surface protective film, comprising a transparent film substrate, an antifouling layer, and a surface protective film in this order, The surface protective film has a base layer and a pressure-sensitive adhesive layer, the antifouling layer and the pressure-sensitive adhesive layer are in contact with each other, the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less; the water contact angle of the main surface of the antifouling layer on the pressure-sensitive adhesive layer side is 115° or more; An optical laminate with a surface protective film, wherein the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0013] [2] The optical laminate with a surface protective film described in [1], wherein the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.30 MPa or more and 3.00 MPa or less.

[0014] [3] The optical laminate with a surface protective film according to [1] or [2], wherein the antifouling layer is a vacuum deposited film.

[0015] [4] The optical laminate with a surface protective film according to any one of [1] to [3] above, wherein the pressure-sensitive adhesive layer has a thickness of 5 μm or more and 50 μm or less.

[0016] [5] The transparent film substrate comprises a transparent film and a hard coat layer provided on a first main surface side of the transparent film; The optical laminate with a surface protective film according to any one of [1] to [4] above, wherein the antifouling layer is provided on the hard coat layer side of the transparent film substrate.

[0017] [6] The optical laminate with a surface protective film according to any one of [1] to [5] above, further comprising an antireflection layer provided between the transparent film substrate and the antifouling layer.

[0018] [7] The optical laminate with a surface protective film according to [6], further comprising a primer layer provided between the transparent film substrate and the antireflection layer. Effect of the Invention

[0019] According to the present invention, it is possible to provide an optical laminate with a surface protective film that can suppress the generation of air bubbles and adhesive residue while improving the antifouling properties. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a cross-sectional view showing an example of an optical laminate with a surface protective film according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited thereto. In addition, all academic and patent documents described in this specification are incorporated herein by reference.

[0022] First, the terms used in this specification will be explained. The "refractive index" is the refractive index for light with a wavelength of 550 nm in an atmosphere at a temperature of 23°C. The "principal surface" of a layered material (more specifically, a pressure-sensitive adhesive layer, a transparent film substrate, an antifouling layer, a surface protective film, a transparent film, a hard coat layer, a primer layer, an antireflection layer, a substrate layer, an optical laminate with a surface protective film, etc.) refers to a surface perpendicular to the thickness direction of the layered material. The "first principal surface" of a layered material means one of the two principal surfaces of the layered material. The "second principal surface" of a layered material means the principal surface opposite to the first principal surface side of the layered material. The "solid content" is a non-volatile component in the composition, for example, a component other than the solvent.

[0023] Unless otherwise specified, the numerical value for the "thickness (film thickness)" of a layered material is the arithmetic average of 10 measured values ​​obtained by observing a cross section of the layered material cut in the thickness direction with an electron microscope, randomly selecting 10 measurement points from the cross-sectional image, and measuring the thickness of the selected 10 measurement points.

[0024] Unless otherwise specified, the number-average primary particle diameter of particles is the number-average value of the circle-equivalent diameters (Heywood diameter: diameter of a circle having the same area as the projected area of ​​a primary particle) of 100 primary particles measured using a scanning electron microscope and image processing software (e.g., "ImageJ" manufactured by the National Institutes of Health, USA).

[0025] Hereinafter, the compound and its derivatives may be collectively referred to by adding "based" after the compound name. In addition, when the polymer name is represented by adding "based" after the compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative, unless otherwise specified. In addition, acrylic and methacrylic may be collectively referred to as "(meth)acrylic". In addition, acrylate and methacrylate may be collectively referred to as "(meth)acrylate".

[0026] Unless otherwise specified, the components and functional groups exemplified in this specification may be used alone or in combination of two or more kinds.

[0027] The drawings referred to in the following description mainly show each component diagrammatically for ease of understanding, and the size, number, shape, etc. of each component shown in the drawings may differ from the actual ones due to the convenience of creating the drawings.

[0028] <Optical laminate with surface protection film> The optical laminate with a surface protective film according to this embodiment (hereinafter sometimes referred to as "optical laminate A") comprises a transparent film substrate, an antifouling layer, and a surface protective film in this order. The surface protective film has a substrate layer and an adhesive layer. The antifouling layer and the adhesive layer are in contact with each other. The surface hardness of the main surface of the adhesive layer facing the antifouling layer is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. The water contact angle of the main surface of the antifouling layer facing the adhesive layer is 115° or more. The adhesion strength between the antifouling layer and the adhesive layer is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0029] The methods for measuring the "surface hardness," "water contact angle," and "adhesion strength" are all the same as the measuring methods in the examples described below or methods equivalent thereto.

[0030] Hereinafter, the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side may be simply referred to as "surface hardness of the pressure-sensitive adhesive layer." Also, the water contact angle of the main surface of the antifouling layer on the pressure-sensitive adhesive layer side may be simply referred to as "water contact angle of the antifouling layer." Also, the numerical ranges of surface hardness "0.01 MPa or more and 0.05 MPa or less" and "0.30 MPa or more and 3.00 MPa or less" may be referred to as "first range" and "second range," respectively.

[0031] The optical laminate A has the above-mentioned configuration, and therefore can improve the antifouling properties while suppressing the generation of air bubbles and adhesive residue. The reason for this is presumed to be as follows.

[0032] In the optical laminate A, the water contact angle of the antifouling layer is 115° or more, so that when the optical laminate A is used (after the surface protection film is peeled off from the antifouling layer), the influence of contamination from the external environment (fingerprints, hand dirt, dust, etc.) can be reduced, and contaminants attached to the surface of the antifouling layer can be easily removed. Therefore, the optical laminate A can improve the antifouling properties.

[0033] On the other hand, when the water contact angle of the antifouling layer is 115° or more, the adhesion between the antifouling layer and the surface protection film is usually low, and air bubbles are likely to occur between the pressure-sensitive adhesive layer of the surface protection film and the antifouling layer during the high-temperature and high-pressure process. In contrast, in the optical laminate A, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is ensured to be 0.01 N / 50 mm or more, while the surface hardness of the pressure-sensitive adhesive layer is within the first range or the second range, so that the generation of air bubbles is suppressed. In detail, when the surface hardness of the pressure-sensitive adhesive layer is within the first range (0.01 MPa or more and 0.05 MPa or less), the pressure-sensitive adhesive layer is easily adapted to the surface shape of the antifouling layer, and the generation of air bubbles is suppressed between the pressure-sensitive adhesive layer and the antifouling layer. On the other hand, when the surface hardness of the pressure-sensitive adhesive layer is within the second range (0.30 MPa or more and 3.00 MPa or less), the deformation of the pressure-sensitive adhesive layer is suppressed, so that the generation of air bubbles is suppressed between the pressure-sensitive adhesive layer and the antifouling layer.

[0034] In addition, in the optical laminate A, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is 0.15 N / 50 mm or less, so that when the surface protection film is peeled off from the antifouling layer, the occurrence of adhesive residue on the surface of the antifouling layer can be suppressed.

[0035] In this embodiment, when the surface hardness of the pressure-sensitive adhesive layer is within the first range, in order to further suppress the generation of air bubbles, the surface hardness of the pressure-sensitive adhesive layer is preferably 0.01 MPa or more and 0.04 MPa or less, more preferably 0.01 MPa or more and 0.03 MPa or less, and even more preferably 0.01 MPa or more and 0.02 MPa or less.

[0036] In this embodiment, when the surface hardness of the pressure-sensitive adhesive layer is within the second range, in order to further suppress the generation of bubbles, the surface hardness of the pressure-sensitive adhesive layer is preferably 0.40 MPa or more, more preferably 0.50 MPa or more, even more preferably 0.60 MPa or more, and even more preferably more than 0.60 MPa, and may be 0.61 MPa or more, 0.62 MPa or more, 0.63 MPa or more, 0.64 MPa or more, 0.65 MPa or more, 0.66 MPa or more, 0.67 MPa or more, 0.68 MPa or more, 0.69 MPa or more, or 0.70 MPa or more. In addition, in this embodiment, when the surface hardness of the pressure-sensitive adhesive layer is within the second range, in order to easily adjust the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer to 0.01 N / 50 mm or more, the surface hardness of the pressure-sensitive adhesive layer is preferably 2.50 MPa or less, and more preferably 2.00 MPa or less.

[0037] In this embodiment, in order to further suppress the occurrence of air bubbles and adhesive residue, the surface hardness of the pressure-sensitive adhesive layer is preferably within the second range.

[0038] In this embodiment, in order to further enhance the antifouling property, the water contact angle of the antifouling layer is preferably 116° or more, more preferably 117° or more, and even more preferably 118° or more. In addition, in this embodiment, in order to easily adjust the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer to 0.01 N / 50 mm or more, the water contact angle of the antifouling layer is preferably 125° or less, and more preferably 120° or less.

[0039] In this embodiment, in order to further suppress the generation of bubbles, the adhesion strength between the antifouling layer and the adhesive layer is preferably 0.02 N / 50 mm or more, more preferably 0.03 N / 50 mm or more, and even more preferably 0.04 N / 50 mm or more. In addition, in this embodiment, in order to further suppress the generation of adhesive residue, the adhesion strength between the antifouling layer and the adhesive layer is preferably 0.14 N / 50 mm or less, more preferably 0.13 N / 50 mm or less, and even more preferably 0.12 N / 50 mm or less.

[0040] Hereinafter, the optical laminate A will be described in detail with reference to the drawings as appropriate. Fig. 1 is a cross-sectional view showing an example of the optical laminate A (optical laminate 10).

[0041] The optical laminate 10 shown in FIG. 1 includes a transparent film substrate 11, an antifouling layer 12, and a surface protective film 13 in this order. The surface protective film 13 includes a substrate layer 14 and an adhesive layer 15. The antifouling layer 12 and the adhesive layer 15 are in contact with each other. The surface hardness of the main surface 15a of the adhesive layer 15 on the antifouling layer 12 side is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. The water contact angle of the main surface 12a of the antifouling layer 12 on the adhesive layer 15 side is 115° or more. The adhesion strength between the antifouling layer 12 and the adhesive layer 15 is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0042] The surface hardness of the main surface 15a of the adhesive layer 15 on the antifouling layer 12 side can be adjusted, for example, by changing at least one of the formulation of the adhesive composition for forming the adhesive layer 15 (for example, the type of base polymer, the type of crosslinking agent, the amount of crosslinking agent, etc.) and the thickness of the adhesive layer 15. The water contact angle of the main surface 12a of the antifouling layer 12 on the adhesive layer 15 side can be adjusted, for example, by changing at least one of the type of antifouling agent for forming the antifouling layer 12, the method for forming the antifouling layer 12, and the thickness of the antifouling layer 12. The adhesion strength between the antifouling layer 12 and the adhesive layer 15 can be adjusted, for example, by changing at least one of the formulation of the adhesive composition for forming the adhesive layer 15 (for example, the type of base polymer, the type of crosslinking agent, the amount of crosslinking agent, etc.), the thickness of the adhesive layer 15, the type of antifouling agent for forming the antifouling layer 12, the method for forming the antifouling layer 12, and the thickness of the antifouling layer 12.

[0043] The surface protective film 13 has a base layer 14 and an adhesive layer 15 laminated on the antifouling layer 12 side of the base layer 14. The surface protective film 13 is releasably attached to the antifouling layer 12 by the adhesive layer 15. The main surface of the base layer 14 opposite to the adhesive layer 15 side may be subjected to an antistatic treatment.

[0044] The transparent film substrate 11 includes a transparent film 16 and a hard coat layer 17 provided on the first main surface 16a side of the transparent film 16. The antifouling layer 12 is provided on the hard coat layer 17 side of the transparent film substrate 11. An adhesive layer (not shown) made of a pressure-sensitive adhesive may be provided on the second main surface 16b side of the transparent film 16. When an adhesive layer is provided on the second main surface 16b side of the transparent film 16, a release liner (not shown) may be temporarily attached to the adhesive layer.

[0045] The optical laminate 10 also includes an antireflection layer 20 between the transparent film substrate 11 and the antifouling layer 12. The optical laminate 10 also includes a primer layer 25 between the transparent film substrate 11 and the antireflection layer 20. The optical laminate 10 functions as an antireflection film, for example, by being attached to the surface of an image display panel (not shown).

[0046] The antireflection layer 20 has four layers, namely, a high refractive index layer 21, a low refractive index layer 22, a high refractive index layer 23, and a low refractive index layer 24, in this order from the primer layer 25 side. Details of the high refractive index layer and the low refractive index layer will be described later. The antireflection layer is not limited to a four-layer structure like the antireflection layer 20, and may be a two-layer structure, a three-layer structure, a five-layer structure, or a stacked structure of six or more layers. The antireflection layer is preferably an alternating stack of two or more high refractive index layers and two or more low refractive index layers. In order to reduce reflection at the air interface, it is preferable that the outermost layer of the antireflection layer (the layer farthest from the primer layer) is a low refractive index layer.

[0047] In the example shown in Fig. 1, the transparent film substrate has a hard coat layer, but the transparent film substrate usable in the present invention is not limited to the above example. For example, the transparent film substrate usable in the present invention does not need to have a hard coat layer. When the transparent film substrate does not have a hard coat layer, for example, a transparent film (transparent film 16 in the example shown in Fig. 1) can be used as the transparent film substrate.

[0048] Next, each layer of the optical laminate 10 will be described in detail.

[0049] [Transparent Film 16] The transparent film 16 is, for example, a transparent resin film having flexibility. Examples of materials constituting the transparent film 16 include polyester resin, polyolefin resin, polystyrene resin, acrylic resin, polycarbonate resin, polyethersulfone resin, polysulfone resin, polyamide resin, polyimide resin, cellulose resin, norbornene resin, polyarylate resin, and polyvinyl alcohol resin. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cycloolefin polymer (COP). Examples of cellulose resins include triacetyl cellulose (TAC). These materials may be used alone or in combination of two or more. From the viewpoints of transparency and strength, the material of the transparent film 16 is preferably one selected from the group consisting of polyester resin, polyolefin resin, and cellulose resin, more preferably one selected from the group consisting of PET, COP, and TAC, and even more preferably TAC. In other words, as the transparent film 16, a type of film selected from the group consisting of polyester resin film, polyolefin resin film, and cellulose resin film is preferable, a type of film selected from the group consisting of PET film, COP film, and TAC film is more preferable, and a TAC film is even more preferable.

[0050] From the viewpoint of strength, the transparent film 16 has a thickness of preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. From the viewpoint of handleability, the transparent film 16 has a thickness of preferably 300 μm or less, and more preferably 200 μm or less.

[0051] One or both principal surfaces of the transparent film 16 may be subjected to a surface modification treatment, such as a corona treatment, a plasma treatment, an ozone treatment, a primer treatment, a glow treatment, or a coupling agent treatment.

[0052] From the viewpoint of improving the transparency of the optical laminate 10, the transparent film 16 preferably has a total light transmittance (JIS K 7375-2008) of 80% or more, more preferably 90% or more, and even more preferably 95% or more and 100% or less.

[0053] [Hard coat layer 17] The hard coat layer 17 is a layer that enhances mechanical properties such as hardness and elastic modulus of the optical laminate 10. The hard coat layer 17 is made of, for example, a cured product of a curable resin composition (composition for forming a hard coat layer). Examples of the curable resin contained in the curable resin composition include polyester resin, acrylic resin, urethane resin, urethane acrylate resin, amide resin, silicone resin, epoxy resin, and melamine resin. These curable resins may be used alone or in combination of two or more kinds. From the viewpoint of enhancing the hardness of the hard coat layer 17, the curable resin is preferably one or more kinds selected from the group consisting of acrylic resin and urethane acrylate resin, and more preferably urethane acrylate resin.

[0054] Examples of the curable resin composition include an ultraviolet-curable resin composition and a thermosetting resin composition. From the viewpoint of improving the productivity of the optical laminate 10, the curable resin composition is preferably an ultraviolet-curable resin composition. The ultraviolet-curable resin composition includes one or more selected from the group consisting of an ultraviolet-curable monomer, an ultraviolet-curable oligomer, and an ultraviolet-curable polymer. A specific example of the ultraviolet-curable resin composition is a composition for forming a hard coat layer described in JP 2016-179686 A.

[0055] The curable resin composition may contain particles having a number-average primary particle diameter of 1.0 μm or more (hereinafter, sometimes referred to as "microparticles"). That is, the hard coat layer 17 may contain microparticles. By blending microparticles in the curable resin composition, it is possible to adjust the hardness, surface roughness, refractive index, and antiglare properties of the hard coat layer 17. Examples of the microparticles include metal (or semi-metal) oxide particles, glass particles, and organic particles. Examples of materials for the metal (or semi-metal) oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials for the organic particles include silicone, polymethyl methacrylate, polystyrene, polyurethane, (meth)acrylate compound-styrene copolymer, benzoguanamine, melamine, polymethylsilsesquioxane, and polycarbonate.

[0056] In order to easily adjust the antiglare property of the hard coat layer 17, the number average primary particle diameter of the microparticles is preferably 1.0 μm or more and 5.0 μm or less, and more preferably 2.0 μm or more and 4.0 μm or less.

[0057] In order to easily adjust the antiglare property of the hard coat layer 17, the amount of the microparticles in the hard coat layer 17 is preferably 0.5 parts by weight or more relative to 100 parts by weight of the curable resin. The upper limit of the amount of the microparticles in the hard coat layer 17 is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight relative to 100 parts by weight of the curable resin.

[0058] When the hard coat layer 17 contains microparticles, unevenness is formed on the surface of the hard coat layer 17, and the uneven shape tends to be reflected on the surface of the antifouling layer 12. When the uneven shape of the surface of the hard coat layer 17 is reflected on the surface of the antifouling layer 12, air bubbles are usually likely to be generated between the pressure-sensitive adhesive layer 15 and the antifouling layer 12 in a high-temperature, high-pressure process. In contrast, in the optical laminate 10, the adhesion strength between the antifouling layer 12 and the pressure-sensitive adhesive layer 15 is ensured to be 0.01 N / 50 mm or more, while the surface hardness of the pressure-sensitive adhesive layer 15 is within the first range or the second range, so that the generation of air bubbles is suppressed.

[0059] The curable resin composition may contain particles having a number-average primary particle diameter of less than 1.0 μm (hereinafter, may be referred to as "nanoparticles"). That is, the hard coat layer 17 may contain nanoparticles. When the hard coat layer 17 is made of a cured product of a curable resin composition containing nanoparticles, fine irregularities are formed on the surface of the hard coat layer 17, and the adhesion between the hard coat layer 17 and a layer (e.g., primer layer 25) formed thereon tends to be improved.

[0060] From the viewpoint of forming a fine uneven shape that contributes to improving adhesion, the number average primary particle diameter of the nanoparticles is preferably 20 nm or more and 80 nm or less, more preferably 25 nm or more and 70 nm or less, and even more preferably 30 nm or more and 60 nm or less.

[0061] As the material of the nanoparticles, inorganic oxides are preferred. Examples of inorganic oxides include oxides of metals (or semi-metals) such as silicon oxide (silica), titanium oxide, aluminum oxide, zirconium oxide, niobium oxide, zinc oxide, tin oxide, cerium oxide, and magnesium oxide. The inorganic oxide may be a composite oxide of a plurality of (semi-)metals. Among the inorganic oxides exemplified above, silicon oxide is preferred because of its high effect of improving adhesion. In other words, as the nanoparticles, silicon oxide particles (silica particles) are preferred. Functional groups such as acrylic groups and epoxy groups may be introduced to the surfaces of inorganic oxide particles as nanoparticles in order to improve adhesion and affinity with resins.

[0062] The amount of nanoparticles in the hard coat layer 17 is preferably 5 parts by weight or more, and may be 10 parts by weight or more, 20 parts by weight or more, or 30 parts by weight or more, relative to 100 parts by weight of the curable resin. If the amount of nanoparticles is 5 parts by weight or more, it is possible to further improve the adhesion with the layer formed on the hard coat layer 17. The upper limit of the amount of nanoparticles in the hard coat layer 17 is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight, relative to 100 parts by weight of the curable resin.

[0063] The thickness of the hard coat layer 17 is preferably 1 μm or more, more preferably 2 μm or more, from the viewpoint of increasing the hardness of the hard coat layer 17. The thickness of the hard coat layer 17 is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 35 μm or less, and even more preferably 30 μm or less, from the viewpoint of ensuring the flexibility of the optical laminate 10.

[0064] The main surface of the hard coat layer 17 opposite to the transparent film 16 side may be subjected to a surface modification treatment. Examples of the surface modification treatment include plasma treatment, corona treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment. In order to increase the adhesion between the hard coat layer 17 and a layer (e.g., a primer layer 25 described later) provided on the side opposite to the transparent film 16 side of the hard coat layer 17, it is preferable that the main surface of the hard coat layer 17 opposite to the transparent film 16 side is subjected to plasma treatment.

[0065] (Method of forming hard coat layer 17) The hard coat layer 17 is formed, for example, by applying a curable resin composition (composition for forming a hard coat layer) to the first main surface 16a of the transparent film 16, and removing the solvent and curing the resin as necessary. The composition for forming a hard coat layer contains, for example, the above-mentioned curable resin and a polymerization initiator (e.g., a photopolymerization initiator), and contains, as necessary, a solvent capable of dissolving or dispersing these components.

[0066] In addition to the above components, the composition for forming a hard coat layer may contain additives such as microparticles, nanoparticles, leveling agents, viscosity adjusters (thixotropic agents, thickeners, etc.), antistatic agents, antiblocking agents, dispersants, dispersion stabilizers, antioxidants, UV absorbers, antifoaming agents, surfactants, and lubricants.

[0067] The coating method of the hard coat layer forming composition may be any suitable method such as bar coating, roll coating, gravure coating, rod coating, slot orifice coating, curtain coating, fountain coating, comma coating, etc. The drying temperature of the coating film after coating may be set to an appropriate temperature depending on the composition of the hard coat layer forming composition, for example, 50°C or higher and 150°C or lower. When the resin component in the hard coat layer forming composition is a thermosetting resin, the coating film is cured by heating. When the resin component in the hard coat layer forming composition is a photocurable resin, the coating film is cured by irradiating it with active energy rays such as ultraviolet rays. The integrated light amount of the irradiated light is preferably 100 mJ / cm. 2 More than 500mJ / cm 2 The following is the result.

[0068] [Primer layer 25] In order to increase the adhesion between the transparent film substrate 11 (hard coat layer 17) and the anti-reflection layer 20, it is preferable to provide a primer layer 25 between the transparent film substrate 11 and the anti-reflection layer 20. Examples of materials for the primer layer 25 include metals (or semi-metals) such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, indium, tungsten, aluminum, zirconium, and palladium; alloys of these metals (or semi-metals); and oxides, fluorides, sulfides, or nitrides of these metals (or semi-metals). The oxide constituting the primer layer 25 may be a composite oxide such as indium tin oxide (ITO). Among these, inorganic oxides are preferable as the material for the primer layer 25, silicon oxide, indium oxide, or ITO is more preferable, and SiOx (x<2) is even more preferable.

[0069] In order to ensure the light transmittance of the primer layer 25 while increasing the adhesion between the transparent film substrate 11 and the antireflection layer 20, the thickness of the primer layer 25 is preferably 0.5 nm or more and 20 nm or less, more preferably 0.5 nm or more and 10 nm or less, and even more preferably 1.0 nm or more and 10 nm or less.

[0070] (Method of forming primer layer 25) The method for forming (depositing) the primer layer 25 is not particularly limited, and may be either a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred because they can form a thin film with a uniform thickness. From the viewpoint of increasing productivity, the method for depositing the primer layer 25 is preferably a method in which a film is deposited using a roll-to-roll sputtering deposition device (roll-to-roll sputtering method).

[0071] In the roll-to-roll sputtering method, for example, a primer layer 25 and an anti-reflection layer 20 can be continuously formed while a long film (e.g., a transparent film substrate 11) is transported in the longitudinal direction (MD direction). In the sputtering method, film formation is performed while an inert gas such as argon and, if necessary, a reactive gas such as oxygen are introduced into a film formation chamber. When an oxide layer is formed as the primer layer 25, the oxide layer can be formed by sputtering using either an oxide target or reactive sputtering using a metal (or semi-metal) target.

[0072] Examples of power sources for performing the sputtering method include DC power sources, AC power sources, RF power sources, and MFAC power sources (AC power sources with a frequency band of several kHz to several MHz). The power density when performing the sputtering method is, for example, 0.1 W / cm 2 More than 20W / cm 2 less than or equal to 1 W / cm 2 More than 15W / cm 2The surface temperature of the film-forming roll when performing the sputtering method is, for example, from −25° C. to 25° C., and preferably from −20° C. to 0° C. The pressure in the film-forming chamber when performing the sputtering method is preferably from 0.01 Pa to 10 Pa, more preferably from 0.05 Pa to 5 Pa, and further preferably from 0.1 Pa to 1 Pa.

[0073] [Anti-reflection layer 20] The antireflection layer 20 is preferably made of two or more thin layers with different refractive indexes. In general, the optical film thickness (product of refractive index and thickness) of the thin film of the antireflection layer is adjusted so that the inverted phases of incident light and reflected light cancel each other out. By making the antireflection layer a multilayer laminate of two or more thin films with different refractive indexes, the reflectance can be reduced in a wide wavelength range of visible light.

[0074] Examples of the thin film material constituting the antireflection layer 20 include metal (or semi-metal) oxides, nitrides, fluorides, etc. The antireflection layer 20 is preferably an alternating laminate of high refractive index layers and low refractive index layers.

[0075] The high refractive index layer has a refractive index of, for example, 1.9 or more, preferably 2.0 or more. Examples of materials for the high refractive index layer include titanium oxide, niobium oxide (Nb2O5, etc.), zirconium oxide, tantalum oxide, zinc oxide, indium oxide, ITO, and antimony-doped tin oxide (ATO). Among these, at least one selected from the group consisting of titanium oxide and niobium oxide is preferred. The low refractive index layer has a refractive index of, for example, 1.6 or less, preferably 1.5 or less. Examples of materials for the low refractive index layer include silicon oxide (SiO2, etc.), titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Among these, silicon oxide is preferred. In particular, it is preferred to alternately stack a niobium oxide thin film as the high refractive index layer and a silicon oxide thin film as the low refractive index layer. In addition to the low refractive index layer and the high refractive index layer, a medium refractive index layer having a refractive index of more than 1.6 and less than 1.9 may be provided.

[0076] The thickness of each of the high refractive index layer and the low refractive index layer is preferably 5 nm to 200 nm, more preferably 10 nm to 150 nm. The thickness of each layer may be designed so that the reflectance of visible light is small according to the refractive index and the layer structure.

[0077] When the antireflection layer 20 is a four-layer alternating laminate in which niobium oxide thin films as high refractive index layers and silicon oxide thin films as low refractive index layers are alternately laminated, the antireflection layer 20 can be configured to have, from the hard coat layer 17 side, a niobium oxide thin film with a thickness of 5 nm to 20 nm, a silicon oxide thin film with a thickness of 10 nm to 40 nm, a niobium oxide thin film with a thickness of 65 nm to 120 nm, and a silicon oxide thin film with a thickness of 60 nm to 100 nm, in this order.

[0078] In order to obtain an antireflection layer 20 having excellent bending resistance, the thickness of the antireflection layer 20 is preferably 140 nm or more and 280 nm or less, more preferably 170 nm or more and 280 nm or less, even more preferably 180 nm or more and 260 nm or less, and even more preferably 190 nm or more and 250 nm or less. In this specification, the "thickness of the antireflection layer" refers to the sum of the thicknesses of the layers constituting the antireflection layer (total thickness).

[0079] (Method of forming antireflection layer 20) The antireflection layer 20 is formed (deposited) on, for example, the primer layer 25 by a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred because they can form a thin film with a uniform thickness. From the viewpoint of increasing productivity, a roll-to-roll sputtering method is preferred as a method for depositing the antireflection layer 20. When the sputtering method is employed, the deposition conditions can be appropriately set, for example, among the conditions explained above (Method for forming the primer layer 25).

[0080] [Anti-stain layer 12] The antifouling layer 12 is provided for the purpose of preventing contamination from the external environment and facilitating the removal of adhering contaminants. In order to suppress a decrease in the antireflection performance of the antireflection layer 20, it is preferable that the antifouling layer 12 has a small refractive index difference with the outermost layer (e.g., a silicon oxide layer) of the antireflection layer 20. The refractive index of the antifouling layer 12 is preferably 1.6 or less, more preferably 1.55 or less.

[0081] The antifouling layer 12 preferably contains, as an antifouling agent, a fluorine-containing compound having an end structure represented by the chemical formula CF3O- (more specifically, CF3-O-). A fluorine-containing compound having an end structure represented by the chemical formula CF3O- can contribute to a lower refractive index while having excellent antifouling properties. Among these, an alkoxysilane compound containing a perfluoropolyether skeleton is preferred as the fluorine-containing compound, since it has excellent water repellency and can exhibit high antifouling properties. Examples of alkoxysilane compounds containing a perfluoropolyether skeleton include compounds represented by the following general formula: CF3-(OCF2) m -(OC2F4) n -O-(CH2)3-Si(OCH3)3

[0082] In the above general formula, m represents an integer of 1 or more and 51 or less, and n represents an integer of 1 or more and 50 or less.

[0083] The fluorine-containing compound having a terminal structure represented by the chemical formula CFO- may be used alone or in combination of two or more. When the alkoxysilane compound is used as the fluorine-containing compound, the alkoxysilane compound may be present in the antifouling layer 12 in a state in which the terminal alkoxy group is reacted (crosslinked).

[0084] The thickness of the antifouling layer 12 is, for example, 2 nm or more and 50 nm or less. The thicker the antifouling layer 12, the more improved the antifouling properties tend to be. The thickness of the antifouling layer 12 is preferably 5 nm or more, more preferably 6 nm or more, and even more preferably 7 nm or more. On the other hand, in order to further suppress the reflection of external light, the thickness of the antifouling layer 12 is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less.

[0085] (Method of forming antifouling layer 12) The antifouling layer 12 is formed, for example, on the antireflection layer 20 by a wet coating method (application method) or a dry coating method. When a fluorine-containing compound is used as a material, in order to form a uniform film of the fluorine-containing compound, it is preferable to form the antifouling layer 12 by a dry coating method. Examples of the dry coating method include a vacuum deposition method, a sputtering method, and a CVD method, and the vacuum deposition method is preferable. In particular, in order to easily adjust the water contact angle of the antifouling layer 12 to 115° or more, it is preferable to form the antifouling layer 12 by a vacuum deposition method. That is, in order to easily adjust the water contact angle of the antifouling layer 12 to 115° or more, it is preferable that the antifouling layer 12 is a vacuum deposition film.

[0086] [Base material layer 14] The base layer 14 is formed of, for example, any suitable film. Examples of the material of the film include polyester resins such as polyethylene terephthalate resins, polycycloolefin resins such as polynorbornene resins, polyolefin resins such as polypropylene, polyamide resins, polycarbonate resins, and copolymer resins thereof. In order to increase the hardness of the base layer 14, polyester resins are preferred as the material of the base layer 14. The thickness of the base layer 14 is, for example, 10 μm or more and 200 μm or less, and preferably 20 μm or more and 150 μm or less. The base layer 14 may be a laminate of two or more layers.

[0087] [Adhesive layer 15] In order to increase the adhesive strength to the antifouling layer 12 having a large water contact angle and to further suppress the generation of bubbles, the thickness of the pressure-sensitive adhesive layer 15 is preferably 5 μm or more, and more preferably 10 μm or more. In order to further suppress the generation of adhesive residue, the thickness of the pressure-sensitive adhesive layer 15 is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 35 μm or less.

[0088] The composition of the adhesive constituting the adhesive layer 15 is not particularly limited, and an appropriate adhesive having a base polymer such as an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyvinyl ether, a vinyl acetate / vinyl chloride copolymer, a modified polyolefin, an epoxy-based polymer, a fluorine-based polymer, a natural rubber, a synthetic rubber, etc. In particular, an acrylic adhesive having an acrylic polymer as a base polymer is preferably used because of its excellent adhesiveness and optical transparency.

[0089] As the acrylic base polymer of the acrylic pressure-sensitive adhesive, one having a monomer unit of (meth)acrylic acid alkyl ester as the main skeleton is suitably used.

[0090] As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 20 carbon atoms is suitably used. For example, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, Examples of such acrylates include isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridodecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, and nonadecyl (meth)acrylate.

[0091] The content of the (meth)acrylic acid alkyl ester unit is preferably 40% by weight or more, more preferably 50% by weight or more, and even more preferably 60% by weight or more, based on the total amount of monomer units constituting the acrylic polymer. The acrylic polymer may be a copolymer of a plurality of kinds of (meth)acrylic acid alkyl esters. The arrangement of the constituent monomer units may be random or block.

[0092] The acrylic adhesive preferably contains a monomer component having a crosslinkable functional group as a copolymerization component. Examples of the monomer having a crosslinkable functional group include a hydroxyl group-containing monomer and a carboxyl group-containing monomer. Among them, it is preferable to contain a hydroxyl group-containing monomer as a copolymerization component. The hydroxyl group and the carboxyl group become reaction sites with the crosslinking agent described below. By introducing a crosslinked structure into the base polymer, the cohesive strength of the adhesive is improved, the adhesive exhibits appropriate adhesive strength to the adherend (antifouling layer 12), and the surface protective film 13 is easily peeled off from the adherend, which tends to suppress contamination caused by adhesive residue and the like.

[0093] Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, etc. Examples of the carboxy group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc.

[0094] In addition to the above, the acrylic pressure-sensitive adhesive may contain, as a copolymerizable monomer component, an acid anhydride group-containing monomer, a caprolactone adduct of acrylic acid, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, or the like. In addition, as the modifying monomer, vinyl monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and acrylic ester monomers such as 2-methoxyethyl acrylate can also be used.

[0095] The ratio of copolymerizable monomer components in the acrylic pressure-sensitive adhesive is not particularly limited, but for example, when a hydroxyl group-containing monomer or a carboxyl group-containing monomer is used as a copolymerizable monomer component for the purpose of introducing crosslinking points, the total content of the hydroxyl group-containing monomer and the carboxyl group-containing monomer is preferably 1 wt % or more and 20 wt % or less, and more preferably 2 wt % or more and 15 wt % or less, of the total amount of the monomer components constituting the acrylic polymer.

[0096] The monomer components are polymerized by various known methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization to obtain an acrylic polymer. From the viewpoint of the balance of properties such as adhesive strength and holding power of the adhesive, and the cost, the solution polymerization method is preferred. As the solvent for solution polymerization, ethyl acetate, toluene, etc. are used. The solution concentration is, for example, 5% by weight or more and 80% by weight or less. As the polymerization initiator, various known ones such as azo-based and peroxide-based ones can be used. A chain transfer agent may be used to adjust the molecular weight. The reaction temperature is, for example, 50°C or more and 100°C or less, and the reaction time is, for example, 1 hour or more and 15 hours or less.

[0097] The molecular weight of the acrylic polymer is appropriately adjusted so that the pressure-sensitive adhesive layer 15 has a desired adhesive strength, and the weight average molecular weight in terms of polystyrene is, for example, from 50,000 to 2,000,000, preferably from 70,000 to 1,800,000, more preferably from 100,000 to 1,500,000, and even more preferably from 200,000 to 1,000,000. When a crosslinked structure is introduced into the acrylic base polymer, it is preferable that the molecular weight of the polymer before the introduction of the crosslinked structure is in the above range.

[0098] When introducing a crosslinked structure into an acrylic base polymer, for example, a crosslinking agent is added to the acrylic polymer solution after polymerization, and the crosslinked structure is introduced by heating as necessary. Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate-based crosslinking agents. Among them, one or more types selected from the group consisting of isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred because they have high reactivity with the hydroxyl group and carboxyl group of the acrylic polymer and are easy to introduce a crosslinked structure. These crosslinking agents react with functional groups such as hydroxyl groups and carboxyl groups introduced into the polymer to form a crosslinked structure.

[0099] As the isocyanate crosslinking agent, polyisocyanate having two or more isocyanate groups in one molecule is used. As the isocyanate crosslinking agent, for example, lower aliphatic polyisocyanate compounds such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanate compounds such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate; aromatic isocyanate compounds such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate; isocyanate adducts such as tolylene diisocyanate trimer adduct of trimethylolpropane, hexamethylene diisocyanate trimer adduct of trimethylolpropane, xylylene diisocyanate trimethylolpropane adduct, and isocyanurate of hexamethylene diisocyanate.

[0100] The epoxy crosslinking agent is a polyfunctional epoxy compound having two or more epoxy groups in one molecule. The epoxy group of the epoxy crosslinking agent may be a glycidyl group. Examples of epoxy crosslinking agents include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, and bisphenol-S-diglycidyl ether. As the epoxy-based crosslinking agent, commercially available products such as "Denacol" manufactured by Nagase ChemteX Corporation, "Tetrad X" manufactured by Mitsubishi Gas Chemical Company, Inc., and "Tetrad C" manufactured by Mitsubishi Gas Chemical Company, Inc. may be used.

[0101] When a crosslinking agent is added to the acrylic polymer after polymerization to introduce a crosslinked structure, the amount of the crosslinking agent used may be appropriately adjusted according to the composition and molecular weight of the polymer, the desired adhesive properties, etc. In order to provide the pressure-sensitive adhesive with an appropriate cohesive force and adjust the peeling force when peeling the protective film from the adherend to an appropriate range, the amount of the crosslinking agent used is preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, and even more preferably 2 parts by weight or more, relative to 100 parts by weight of the acrylic polymer. In addition, in order to provide an appropriate adhesive property to the adherend, the amount of the crosslinking agent used is preferably 15 parts by weight or less, more preferably 14 parts by weight or less, relative to 100 parts by weight of the acrylic polymer.

[0102] The surface hardness of the adhesive layer 15 tends to increase with an increase in the amount of crosslinking agent used, but if the amount of crosslinking agent used is excessively increased, the amount of unreacted crosslinking agent tends to increase. Since the unreacted crosslinking agent functions as a plasticizer, if the amount of crosslinking agent used is excessively increased, the surface hardness of the adhesive layer 15 tends to decrease.

[0103] From the viewpoint of making the surface hardness of the adhesive layer 15 within the first or second range and suppressing the contamination of the antifouling layer 12 caused by the crosslinking agent, it is preferable to adjust the ratio of the crosslinkable functional group of the acrylic polymer to the reactive functional group of the crosslinking agent within an appropriate range. The amount of the crosslinking agent added is preferably adjusted so that the molar equivalent of the reactive functional group of the crosslinking agent is within a range of 0.2 to 1.2 times the molar equivalent of the crosslinkable functional group of the acrylic polymer. For example, when an isocyanate crosslinking agent is used, it is preferable to adjust the amount of the crosslinking agent so that the molar equivalent of the isocyanate group is 0.2 to 1.2 times the molar equivalent of the hydroxyl group of the acrylic polymer. When an epoxy crosslinking agent is used, it is preferable to adjust the amount of the crosslinking agent so that the molar equivalent of the epoxy group is 0.2 to 1.2 times the molar equivalent of the carboxyl group of the acrylic polymer. It is more preferable that the molar equivalent of the reactive functional group of the crosslinking agent is 0.2 to 1.0 times the molar equivalent of the crosslinkable functional group of the acrylic polymer.

[0104] The adhesive composition for forming the adhesive layer 15 contains a base polymer, and if necessary, a crosslinking agent and a solvent. The adhesive composition may contain additives such as a polymerization catalyst, a crosslinking catalyst, a silane coupling agent, a tackifier, a plasticizer, a softener, an antidegradant, a filler, a colorant, an ultraviolet absorber, an antioxidant, a surfactant, and an antistatic agent, within the range that does not impair the characteristics of the present invention.

[0105] The adhesive composition is applied onto a film to be the base layer 14 by roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coating, or the like, and the solvent is dried and removed as necessary to form the adhesive layer 15. As the drying method, an appropriate method can be adopted as appropriate. The drying temperature is preferably 40°C or higher and 200°C or lower, more preferably 50°C or higher and 180°C or lower. The drying time is preferably 5 seconds or higher and 20 minutes or lower, more preferably 5 seconds or higher and 10 minutes or lower.

[0106] When the adhesive composition contains a crosslinking agent, it is preferable to proceed with crosslinking by heating or aging simultaneously with or after drying of the solvent. When the adhesive composition contains a constituent monomer component of the base polymer, it is preferable to carry out polymerization by heating or aging. The heating temperature and heating time are appropriately set according to the type of monomer or crosslinking agent used, and for example, the heating temperature is in the range of 20°C or more and 160°C or less, and the heating time is in the range of 1 minute or more and 7 days or less. Heating for drying and removing the solvent may also serve as heating for polymerization or crosslinking.

[0107] [Preferable embodiment of optical laminate A] In this embodiment, in order to enhance the antifouling properties while further suppressing the occurrence of air bubbles and adhesive residue, it is preferable that the optical laminate A satisfies the following condition 1, it is more preferable that it satisfies the following condition 2, and it is even more preferable that it satisfies the following condition 3. Condition 1: The surface hardness of the main surface of the pressure-sensitive adhesive layer on the side of the antifouling layer is 0.30 MPa or more and 3.00 MPa or less, and the antifouling layer is a vacuum-deposited film. Condition 2: The above condition 1 is satisfied, and the thickness of the adhesive layer is 5 μm or more and 50 μm or less. Requirement 3: The above Requirement 2 is satisfied, and the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is greater than 0.60 MPa.

[0108] [Other embodiments] Although the optical laminate with a surface protective film according to the present embodiment has been described above, the present invention is not limited to the above-mentioned embodiment. For example, the optical laminate with a surface protective film according to the present invention may not include a primer layer and an antireflection layer. In addition, the optical laminate with a surface protective film according to the present invention may include an optical functional layer different from the layer included in the above-mentioned configuration. EXAMPLES

[0109] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0110] <Preparation of optical laminate of Example 1> Hereinafter, there will be described a method for producing the optical laminate of Example 1. First, a method for producing the antireflection film will be described.

[0111] [Preparation of anti-reflective film] (Hard coat layer forming process) The mixture was prepared by mixing 100 parts by weight (solid content equivalent) of a urethane acrylate-based ultraviolet-curable resin composition containing silica particles having a number-average primary particle diameter of 50 nm ("Beamset 577" manufactured by Arakawa Chemical Industries Co., Ltd.), 0.4 parts by weight of silicone resin particles ("Tospearl 130" manufactured by Momentive Performance Materials Japan, Inc., average particle diameter: 3.0 μm, refractive index: 1.43, true specific gravity: 1.32), 0.5 parts by weight of crosslinked polymethyl methacrylate (PMMA) particles ("Techpolymer SSX-103" manufactured by Sekisui Chemical Co., Ltd., average particle diameter: 3.0 μm, refractive index: 1.50, true specific gravity: 1.20), 2.0 parts by weight of a thixotropic agent ("Sumecton SAN" manufactured by Kunimine Kogyo Co., Ltd., a synthetic smectite which is an organic clay), and a photopolymerization initiator (IGM 1.5 parts by weight of a silicone leveling agent ("Omnirad127" manufactured by Resins Co., Ltd.) and 0.15 parts by weight of a silicone-based leveling agent ("Polyflow LE303" manufactured by Kyoeisha Chemical Co., Ltd.) were mixed and diluted with butyl acetate to obtain a composition HC1 for forming a hard coat layer with a solid content concentration of 42% by weight. Next, the composition HC1 for forming a hard coat layer obtained by the above procedure was applied to one main surface of a TAC film ("Fujitac TG60UL" manufactured by Fujifilm Co., Ltd., thickness: 60 μm) as a transparent film to form a coating film. Next, this coating film was dried by heating at a temperature of 60° C. for 60 seconds, and then cured by ultraviolet irradiation. When irradiating with ultraviolet rays, a high-pressure mercury lamp was used as a light source, ultraviolet rays with a wavelength of 365 nm were used, and the accumulated light amount was 300 mJ / cm 2 2 As a result, a hard coat layer with a thickness of 6 μm was formed on the TAC film.

[0112] (Surface modification process of hard coat layer) Next, the surface of the hard coat layer was plasma-treated using a roll-to-roll plasma treatment device while transporting the TAC film (transparent film substrate) on which the hard coat layer was formed, in a vacuum atmosphere of 0.5 Pa. During the plasma treatment, argon gas was used as the inert gas, and the effective power density was 0.02 W·min / cm. 2·m. As a result, a laminate (hereinafter, sometimes referred to as "optical film F1") including a TAC film and a plasma-treated hard coat layer was obtained. The effective power density is the power density of the plasma output (W / cm 2 ) divided by the film transport speed (m / min) when using the roll-to-roll method.

[0113] Next, the primer layer forming process and the anti-reflection layer forming process will be described. In the primer layer forming process and the anti-reflection layer forming process, when forming the oxide film, the film was formed while introducing argon gas and oxygen gas into the film forming chamber. When forming the oxide film, the pressure was kept constant by adjusting the amount of argon gas introduced and exhausted, and the amount of oxygen gas introduced was adjusted by plasma emission monitoring (PEM) control so that the film formation mode was maintained in the transition region.

[0114] (Primer layer formation process) The optical film F1 obtained by the above procedure was introduced into a roll-to-roll sputtering deposition apparatus, and the deposition chamber was filled with 1×10 -4 The pressure was reduced to 1 Pa. Next, while conveying the optical film F1, the surface temperature of the film-forming roll was set to -8°C, and a SiOx layer (x<2) having a thickness of 3.5 nm was formed (deposited) as a primer layer on one main surface of the hard coat layer by a reactive sputtering method. A Si target was used as the target material for forming the primer layer.

[0115] (Anti-reflection layer formation process) Following the formation of the primer layer, the optical film F1 after the formation of the primer layer was transported using a roll-to-roll sputtering deposition apparatus, while the following layers were deposited in this order on one main surface of the primer layer by reactive sputtering: a first layer: a niobium oxide layer having a thickness of 10.1 nm (refractive index: 2.33), a second layer: a silicon oxide layer having a thickness of 27.5 nm (refractive index: 1.46), a third layer: a niobium oxide layer having a thickness of 105.0 nm, and a fourth layer: a silicon oxide layer having a thickness of 83.5 nm. Note that a Si target was used for depositing the silicon oxide layer, and a Nb target was used for depositing the niobium oxide layer. As a result, an antireflection layer having a four-layer structure (a four-layer structure consisting of a first layer, a second layer, a third layer, and a fourth layer) was formed on one main surface of the primer layer.

[0116] (Anti-stain layer formation process) A coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient (antifouling agent): alkoxysilane compound containing a perfluoropolyether skeleton) was dried and solidified and used as a deposition source, and an antifouling layer having a thickness of 8 nm was formed on the antireflection layer by vacuum deposition at a heating temperature of 260° C. This resulted in an antireflection film AR1 having a TAC film, a hard coat layer, a primer layer, an antireflection layer, and an antifouling layer in this order.

[0117] [Preparation of surface protection film] (Preparation of Pressure Sensitive Adhesive Composition PS1) In a reaction vessel equipped with a thermometer, a stirrer, a cooler, and a nitrogen gas inlet tube, 100 parts by weight of 2-ethylhexyl acrylate, 80 parts by weight of vinyl acetate, and 5 parts by weight of acrylic acid as monomer components, 0.3 parts by weight of a polymerization initiator (NOF Corp.'s "Niper BW"), and 2400 parts by weight of toluene were placed, and nitrogen substitution was performed by introducing nitrogen gas while stirring the contents of the vessel while maintaining the temperature at 23°C. Thereafter, the temperature of the vessel contents was maintained at 65°C and a polymerization reaction was performed for 6 hours. Next, the temperature of the vessel contents was raised to 95°C, and the temperature of the vessel contents was maintained at 95°C for 8 hours. Next, the vessel contents were cooled to obtain a solution of an acrylic polymer with a weight average molecular weight of 470,000 (solid concentration: 38% by weight). To 100 parts by weight (solid content) of the obtained acrylic polymer solution, 2 parts by weight of a tetrafunctional epoxy compound ("Tetrad C" manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added as a crosslinking agent, and then diluted with methyl ethyl ketone to obtain a pressure-sensitive adhesive composition PS1 with a solid content concentration of 20% by weight. The molar equivalent of the epoxy group of the crosslinking agent in the pressure-sensitive adhesive composition PS1 was 0.29 times the molar equivalent of the carboxy group of the polymer.

[0118] (Formation of adhesive layer) The above-mentioned adhesive composition PS1 was applied to the second main surface of a 38 μm-thick PET film ("Diafoil T100G38" manufactured by Mitsubishi Chemical Corporation) whose first main surface was treated for antistatic purposes, and dried for 2 minutes at a temperature of 130° C. to form an adhesive layer having a thickness of 13 μm. Then, the release-treated surface of a release liner (a 25 μm-thick PET film with one side release-treated with a silicone-based release agent) was attached to the exposed surface of the adhesive layer to obtain a surface protection film SP1 protected by the release liner.

[0119] [Lamination of surface protection film and anti-reflective film] After the release liner was peeled off from the surface protective film SP1, the pressure-sensitive adhesive layer of the surface protective film SP1 was attached to the antifouling layer surface of the antireflection film AR1 using a roll laminator, thereby obtaining the optical laminate of Example 1 (optical laminate with a surface protective film).

[0120] <Preparation of optical laminates of Examples 2 to 7> The optical laminates of Examples 2 to 7 were obtained in the same manner as in Example 1, except that the amount of a tetrafunctional epoxy compound ("Tetrad C" manufactured by Mitsubishi Gas Chemical Company, Inc.) added when preparing the adhesive composition was changed as follows relative to 100 parts by weight of the polymer. Note that, hereinafter, the adhesive compositions used in Examples 2 to 7 may be referred to as adhesive compositions PS2 to PS7, respectively.

[0121] [Addition amount of tetrafunctional epoxy compound in Examples 2 to 7] Example 2 (adhesive composition PS2): 4 parts by weight Example 3 (adhesive composition PS3): 6 parts by weight Example 4 (adhesive composition PS4): 8 parts by weight Example 5 (adhesive composition PS5): 10 parts by weight Example 6 (adhesive composition PS6): 12 parts by weight Example 7 (adhesive composition PS7): 14 parts by weight

[0122] <Preparation of optical laminate of Example 8> Except for using the pressure-sensitive adhesive composition PS8 instead of the pressure-sensitive adhesive composition PS1 and changing the thickness of the pressure-sensitive adhesive layer to 23 μm, an optical laminate of Example 8 was obtained in the same manner as in Example 1. The pressure-sensitive adhesive composition PS8 was prepared as follows.

[0123] [Preparation of Pressure Sensitive Adhesive Composition PS8] In a reaction vessel equipped with a thermometer, a stirrer, a cooler and a nitrogen gas inlet tube, 96 parts by weight of 2-ethylhexyl acrylate and 4 parts by weight of 2-hydroxyethyl acrylate as monomer components, 0.2 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator and 150 parts by weight of ethyl acetate were placed, and nitrogen gas was introduced while stirring the contents of the vessel, and nitrogen substitution was performed. Thereafter, the temperature of the contents of the vessel was kept at 65°C and a polymerization reaction was performed for 6 hours, to obtain an acrylic polymer solution (solid concentration: 40% by weight). 73 parts by weight of toluene and 10 parts by weight of acetylacetone were added to 250 parts by weight of the obtained acrylic polymer solution (100 parts by weight of polymer), and the concentration was diluted to 30% by weight. To this solution, 1.3 parts by weight (1.0 part by weight as solids) of a 75% by weight ethyl acetate solution of tolylene diisocyanate trimer adduct of trimethylolpropane ("Coronate L" manufactured by Tosoh Corporation) was added as a crosslinking agent, and 4 parts by weight (0.02 part by weight as solids) of a 0.5% by weight solution of dioctyl tin laurate ("Envirizer OL-1" manufactured by Tokyo Fine Chemical Co., Ltd.) was added as a crosslinking catalyst and stirred to obtain a pressure-sensitive adhesive composition PS8. The molar equivalent of the isocyanate group of the crosslinking agent in the pressure-sensitive adhesive composition PS8 was 0.69 times the molar equivalent of the hydroxyl group of the polymer.

[0124] <Preparation of Optical Laminate of Comparative Example 1> Except for using adhesive composition PS9 instead of adhesive composition PS8, an optical laminate of Comparative Example 1 was obtained in the same manner as in Example 8. Adhesive composition PS9 was obtained in the same manner as adhesive composition PS8, except for changing the amount of crosslinker (75 wt% ethyl acetate solution of tolylene diisocyanate trimer adduct of trimethylolpropane) added to 5.3 parts by weight (4.0 parts by weight as solid content).

[0125] <Preparation of Optical Laminate of Comparative Example 2> An optical laminate of Comparative Example 2 was obtained in the same manner as in Example 8, except that the adhesive composition PS10 was used instead of the adhesive composition PS8, and the thickness of the adhesive layer was changed to 21 μm. The adhesive composition PS10 was obtained in the same manner as the adhesive composition PS8, except that the crosslinking agent and the amount of the crosslinking agent added were changed to 17.58 parts by weight of an isocyanurate of hexamethylene diisocyanate ("Coronate HX" manufactured by Tosoh Corporation).

[0126] <Preparation of Optical Laminate of Comparative Example 3> An optical layered body of Comparative Example 3 was obtained in the same manner as in Example 8, except that the antifouling layer forming step was changed as follows.

[0127] [Anti-stain layer forming process of Comparative Example 3] A coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient (antifouling agent): alkoxysilane compound containing a perfluoropolyether skeleton) was applied onto the antireflection layer to form a coating film. The coating film thus formed was then dried by heating at a temperature of 60°C for 60 seconds to form an antifouling layer having a thickness of 8 nm on the antireflection layer.

[0128] <Preparation of Optical Laminate of Comparative Example 4> An optical layered body of Comparative Example 4 was obtained in the same manner as in Comparative Example 1, except that the antifouling layer forming step was changed to the same method as in the above [Antifouling layer forming step of Comparative Example 3].

[0129] <Measurement and evaluation methods> The following describes the surface hardness of the pressure-sensitive adhesive layer of the surface protection film used in the preparation of each optical laminate, the method for measuring the physical properties of each optical laminate, and the method for evaluating each optical laminate. The measurements and evaluations described below were performed in an environment with a temperature of 23° C. and a relative humidity of 50%, unless otherwise specified.

[0130] [Surface hardness of adhesive layer] After the release liner was peeled off, the adhesive layer of each surface protection film was placed facing upward and fixed on the stage of a nanoindenter (Bruker TI950 TriboIndenter). Next, a load was gradually applied to the main surface of the adhesive layer (the surface to be bonded to the antifouling layer) using a Berkovich (triangular pyramid)-shaped diamond indenter (tip curvature radius: 0.1 μm), and the indentation hardness (indentation load / projected contact area between the indenter and the sample) was calculated when the indenter was pressed to a depth of 4000 nm, and the obtained value was taken as the surface hardness of the adhesive layer. The projected contact area between the indenter and the sample was calculated by the method described in JP 2005-195357 A.

[0131] [Water contact angle] Using a contact angle measuring device ("DMo-701" manufactured by Kyowa Interface Science Co., Ltd.), 4.0 μL of water was dropped onto the anti-fouling layer surface (the main surface to which the surface protective film was to be attached) of each optical laminate before the surface protective film was attached, and 2 seconds after the dropping, the angle between the anti-fouling layer surface and the tangent to the end of the droplet was measured.

[0132] [Oleic acid friction test] First, a weight was attached above the sliding part of a linear abrasion tester ("5800" manufactured by Taber Industries) so that the total load during sliding was 2.5 kg. Next, the main surface of the transparent film substrate side of each optical laminate before laminating the surface protective film was laminated to a glass plate, and then 1 mL of oleic acid (manufactured by Hayashi Pure Chemical Industries, Ltd.) was dropped onto the antifouling layer. Next, the position of the sliding part was adjusted so that the tip of the sliding part to which a paper towel ("C-Fold Paper Towels" manufactured by Kimberly-Clark) was attached and the part on the antifouling layer surface where the oleic acid was dropped were in contact. Next, an oleic acid sliding test was performed with the sliding distance (one way in reciprocating motion) of the tip of the sliding part on the antifouling layer surface set to 40 mm, the sliding speed of the tip of the sliding part set to 60 reciprocations / min, and the number of reciprocating motions of the tip of the sliding part against the antifouling layer surface set to 1000 reciprocations. Next, the water contact angle of the antifouling layer surface (sliding surface) after the oleic acid sliding test was measured by the method described above in the section [Water Contact Angle]. When the water contact angle after the oleic acid sliding test was 90° or more, it was evaluated as A (excellent antifouling property). On the other hand, when the water contact angle after the oleic acid sliding test was less than 90°, it was evaluated as B (not excellent antifouling property).

[0133] [Autoclave test] The main surface of each optical laminate on the transparent film substrate side was attached to a glass plate, and then treated in an autoclave set at a temperature of 50°C and a pressure of 0.5 MPa for 15 minutes. After that, each optical laminate was left to stand for 30 minutes in an environment with a temperature of 23°C and a relative humidity of 50%, and the presence or absence of air bubbles at the interface between the surface protection film and the antifouling layer was visually confirmed. If no air bubbles were found, it was evaluated as A (air bubble generation was suppressed). On the other hand, if air bubbles were found, it was evaluated as B (air bubble generation was not suppressed).

[0134] [Adhesion strength] Each optical laminate was cut to a width of 50 mm and a length of 100 mm, and left to stand for 30 minutes in an environment of 23°C and 50% relative humidity, after which the main surface of each optical laminate on the transparent film substrate side was attached to an acrylic plate using double-sided adhesive tape to obtain a measurement sample. Next, the surface protection film at one end of the measurement sample in the longitudinal direction was peeled off, and a peel test was performed under conditions of a peel angle of 180° and a tensile speed of 0.3 m / min, and the obtained peel strength was defined as the adhesion strength between the antifouling layer and the adhesive layer (unit: N / 50 mm).

[0135] <Result> For the optical laminates of Examples 1 to 8 and Comparative Examples 1 to 4, the type of pressure-sensitive adhesive composition used, the surface hardness of the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer, the method for forming the antifouling layer, the water contact angle, the evaluation results of the oleic acid sliding test, the evaluation results of the autoclave test, and the adhesion strength are shown in Table 1. In Table 1, "water contact angle" means the water contact angle of the antifouling layer before the oleic acid sliding test. In Table 1, "adhesion strength" means the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer.

[0136] [Table 1]

[0137] As shown in Table 1, in Examples 1 to 8, the surface hardness of the pressure-sensitive adhesive layer was 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. In Examples 1 to 8, the water contact angle of the antifouling layer before the oleic acid sliding test was 115° or more. In Examples 1 to 8, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer was 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0138] As shown in Table 1, in Examples 1 to 8, the evaluation results of the oleic acid sliding test were A. Thus, the optical laminates of Examples 1 to 8 were excellent in antifouling property. In Examples 1 to 8, the evaluation result of the autoclave test was A. Thus, the optical laminates of Examples 1 to 8 were suppressed in generating bubbles.

[0139] As shown in Table 1, the surface hardness of the pressure-sensitive adhesive layer was more than 0.05 MPa and less than 0.30 MPa in Comparative Examples 1, 2, and 4. In Comparative Examples 3 and 4, the water contact angle of the antifouling layer before the oleic acid sliding test was less than 115°.

[0140] As shown in Table 1, in Comparative Examples 3 and 4, the evaluation results of the oleic acid sliding test were B. Thus, the optical laminates of Comparative Examples 3 and 4 did not have excellent antifouling properties. In Comparative Examples 1 and 2, the evaluation results of the autoclave test were B. Thus, the optical laminates of Comparative Examples 1 and 2 did not suppress bubble generation.

[0141] Regarding the optical laminates of Examples 1 to 8 and Comparative Examples 1 to 4, when the surfaces of the antifouling layers were visually inspected after the adhesion strength was measured, no adhesive residue was found on the surfaces of the antifouling layers.

[0142] The above results demonstrate that the present invention can provide an optical laminate with a surface protective film that can suppress the generation of air bubbles and adhesive residue while improving antifouling properties. [Explanation of symbols]

[0143] 10: Optical laminate 11: Transparent film base 12: Antifouling layer 13: Surface protection film 14: Base material layer 15: Adhesive layer 16: Transparent film 17: Hard coat layer 20: Anti-reflection layer 25: Primer layer

Claims

1. An optical laminate with a surface protective film, comprising a transparent film substrate, an antifouling layer, and a surface protective film in this order, The surface protective film has a base layer and a pressure-sensitive adhesive layer, the antifouling layer and the pressure-sensitive adhesive layer are in contact with each other, the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.01 MPa or more and 0.02 MPa or less, or 0.40 MPa or more and 3.00 MPa or less; a water contact angle of a main surface of the antifouling layer on the pressure-sensitive adhesive layer side is 115° or more and 125° or less; the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less; The surface hardness is an indentation hardness measured when a triangular pyramidal diamond indenter is used to gradually apply a load to the main surface of the pressure-sensitive adhesive layer and indented to a depth of 4000 nm; The adhesion strength is a peel strength obtained by conducting a peel test under conditions of a peel angle of 180° and a tensile speed of 0.3 m / min. of the optical laminate with a surface protective film.

2. 2 . The optical laminate with a surface protective film according to claim 1 , wherein the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.40 MPa or more and 3.00 MPa or less.

3. The optical laminate with a surface protective film according to claim 1 , wherein the antifouling layer is a vacuum deposited film.

4. The optical laminate with a surface protective film according to claim 1 , wherein the pressure-sensitive adhesive layer has a thickness of 5 μm or more and 50 μm or less.

5. The transparent film substrate includes a transparent film and a hard coat layer provided on a first main surface side of the transparent film, The optical laminate with a surface protective film according to claim 1 , wherein the antifouling layer is provided on the hard coat layer side of the transparent film substrate.

6. The optical laminate with a surface protective film according to claim 1 , further comprising an antireflection layer provided between the transparent film substrate and the antifouling layer.

7. The optical laminate with a surface protective film according to claim 6 , further comprising a primer layer provided between the transparent film substrate and the antireflection layer.

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